[Feature Request]: Add `model` Column to Device Model

### Preflight Checklist

- [x] I have read the [Contributing Guidelines](https://github.com/EnAccess/micropowermanager/blob/main/CONTRIBUTING.md) for this project, if it exists.
- [x] I agree to follow the [Code of Conduct](https://github.com/EnAccess/micropowermanager/blob/main/CODE_OF_CONDUCT.md) that this project adheres to.
- [x] I have searched the [issue tracker](https://github.com/EnAccess/micropowermanager/issues) for a feature request that matches the one I want to file, without success.

### Problem Description

Devices in the core data model lack a dedicated “model” field, so the app, APIs, and reports can’t store or display model information cleanly.

### Proposed Solution

- Add a nullable `model` column to the devices table.

- Update the App\Models\Device entity and any validation rules to surface this field.

- Extend relevant controllers/API resources so clients can read and write the model value.

### Alternatives Considered

N/A

### Additional Information

_No response_